Heart Rate Zone Calculator
Training zones turn effort into a number you can actually check. Enter your age and resting heart rate to get all five zones, under either of the two standard methods.
Formula
Maximum heart rate ≈ 220 − age
- Zone range = maximum heart rate × the zone percentage
- The estimate carries a spread of 10 to 12 bpm either way
Age 40: max ≈ 180 bpm, so zone 2 at 60–70% is 108–126 bpm
Estimating Maximum Heart Rate
Every zone is a percentage of your maximum heart rate, estimated here as:
Max HR = 220 − age
At 40, that is 180 beats per minute.
Treat it as a rough anchor. Individual maximums scatter by roughly ±10 to 12 beats per minute around the prediction, and for adults over 50 the Tanaka formula (208 − 0.7 × age) is generally better evidenced.
Two Methods, Two Different Answers
Percentage of max HR takes each zone straight off your maximum. Simple, but blind to your fitness.
Karvonen uses heart rate reserve, so it adapts to you:
Zone = ((Max HR − Resting HR) × %) + Resting HR
For a 40-year-old with a resting heart rate of 60, Zone 2 runs 108–126 by the first method and 132–144 by Karvonen — a gap of 24 beats.
Pick one method and stay with it, or the numbers will never agree.
What the Five Zones Are For
- Zone 1 (50–60%): recovery, warm-ups and cool-downs
- Zone 2 (60–70%): aerobic base, where most training time should sit
- Zone 3 (70–80%): tempo, useful in moderation
- Zone 4 (80–90%): threshold, sustainable for around an hour
- Zone 5 (90–100%): maximum, for short intervals
Quick Reference
| Zone | % of max | Effort | At age 40 |
|---|---|---|---|
| 1 Recovery | 50–60% | Very light, conversational | 90–108 bpm |
| 2 Easy | 60–70% | Aerobic base, can hold a chat | 108–126 bpm |
| 3 Aerobic | 70–80% | Steady, talking gets harder | 126–144 bpm |
| 4 Threshold | 80–90% | Hard, a few words at a time | 144–162 bpm |
| 5 Maximal | 90–100% | All out, minutes at most | 162–180 bpm |
Frequently Asked Questions
- What is Zone 2 training?
- Steady aerobic work at a conversational effort, roughly 60 to 70 per cent of your maximum. It builds the endurance base that supports everything else, and most people run it too fast.
- Which method should I use?
- Karvonen if you know your true resting heart rate, since it accounts for fitness. Percentage of maximum is fine as a rough guide, but it will place your zones lower.
- How do I measure my resting heart rate?
- Take your pulse for a full minute immediately on waking, before getting up, across several days and average it. Many wearables record it automatically overnight.
- Do beta blockers affect my zones?
- Yes, substantially. They lower both resting and maximum heart rate, which makes any age-based estimate unreliable. Ask your doctor how to gauge effort instead.